Quick Tip: Choose The Right File Format For The Job

Being spoiled for choice, when it comes to exporting audio, is common with most DAWs supporting most audio formats in existence. Audio formats can be categorised into three categories: uncompressed, lossless, and lossy. I will explain the popular formats for audio and provide some recommendations for using the right format for the job.

Audio Codec vs Audio Format. These two terms may seem confusing but they are often used to refer to the same thing. A codec is a program to encode and decode data, coder-decoder. Formats usually refer to the file format or extension. Since the codec and file extension are related, the terms could be used interchangeably for non-technical users.

Uncompressed

This is the highest quality audio in its most raw form and perfect for the recording process. You should be using these formats for recording, archiving, and any other audio that should be in its most pristine quality. You can also archive your tracks in this format with hard drives becoming extremely cheap.

WAVE

The actual encoding of the audio is PCM (Pulse Code Modulation) thus you might see this listed as PCM Wave. There are two formats for WAVE files, Microsoft Wave (WAV) and Broadcast Wave (BWF). They share the same .wav file extension. This is the most recommended and universal format for professional audio as it is cross-platform compatible. Broadcast wave has an additional BEXT chunk which allows embedding of additional metadata like title, time-code, origination, etc. Broadcast wave is extremely useful for post production purposes with the additional metadata.

AIFF

The Apple Interchange File Format was developed by Apple. It uses the same PCM encoding as WAVE. This format is commonly found on the Mac OS platform. Although the quality is equivalent to WAVE, there can be incompatibility issues on other platforms like Windows especially within less popular audio software.

SDII

A format created for earlier versions of Pro Tools, it is no longer recommend for use and should be considered obsolete. Support for the format is not a standard in audio software.

Lossless

Useful for archiving final tracks in smaller sizes or distributing high quality tracks. Lossless files have a compression algorithm which reduces file sizes but not lowering audio quality. Lossless files often allow you to reverse the process to retrieve an uncompressed version of the track. The trouble comes as lossless files need a decoder which are uncommon in portable players and not a standard in media players.

FLAC

FLAC provides lossless encoding for audio with files resulting in being 50-60% of their original size. FLAC also provides the ability for better tagging of audio files, cover art, and fast seeking. FLAC is commonly used for digital transfers of high fidelity recordings like classical music or audiophile content. However, FLAC is not supported on most media players.

Apple Lossless

An audio codec developed by Apple for lossless data compression for audio files. It also uses the MP4 container like AAC with the extension .m4a. It is the only lossless compressed audio format natively supported on the iPod. If you use iTunes to organize your music and have an iPod or iPhone, this is the format that you will be using.

Lossy

Lossy audio formats can achieve small file sizes which is very useful for file distribution and storing more songs on portable devices. However, audio quality is very much reduced due to the file size reduction process. You should always ensure that you have an uncompressed master copy of the audio that you are compressing in case you need a high quality version for other purposes. You should not be using lossy formats during the production process as it will greatly degrade your audio.

MP3

This is a very popular music distribution format. Most music that are distributed over the web is in the MP3 format. It is a standard format for portable music players and supported on all platforms.

AAC

Advanced Audio Coding is a newer format that was designed to replace the dated MP3 format. It is designed to achieve better audio quality at similar bit rates. However, it is co-existing rather than replacing the MP3. Audio encoded in this format uses the MPEG-4 container thus the file extension is usually .m4a.

WMA

Developed by Microsoft for the Windows Media Player, the Windows Media Audio format includes DRM(Digital Right Management). Although the regular WMA file is lossy, there is a WMA Lossless format but it is uncommon. I don’t recommend WMA because of its incompatibility with software and media players, as with most proprietary file formats.

OGG

The actual audio codec is OGG Vorbis. OGG Vorbis is rarely used since its support is uncommon. It is more commonly used with video in the OGG container. The file extension are .ogg and .oga

Recommendations

Recording/Audio Editing

The only format that you should be using is WAV or BWF. These are cross-platform compatible and a standard in the industry. AIFF has a possibility of incompatibility on non-Mac systems.

Archiving Final Mixes

You can archive your final mixes in WAV or BWF. If you want to send lossless files to someone else, you can compress the data into FLAC files to reduce the file size. FLAC encoders and decoders are freely available on the web.

Distribution

If you are distributing CDs, always burn using your uncompressed masters. Do not burn the CD using the mp3 files as you always want to distribute the highest audio quality possible. If you need to compress your files for web distribution, mp3 compression is what you need. Go for a high bit rate to keep your music sounding great. 320kbps could be perceived as CD quality on most systems and 160kbps is the lowest you should go. Higher bit rates keep your music sounding better while lower bit rates trash it.

Final Tip

This final tip only applies to uncompressed audio. Without going into details, you should always be recording at 24-bit 44.1 kHz whenever possible. Only convert your audio to CD quality(16-bit, 44.1 kHz) just before burning to a CD. You will want all the headroom you can get during your production process.

Hector Lee is a sound designer and engineer based in Singapore. With experience spanning from sound design and music production to crafting sound art installations, he actively engages in collaborations with artists from other disciplines. His works and collaborations have spanned a wide range including theatre, live electronic music, dance, music composition, audio programming, interactive sound art installations, etc. He also blogs about music and audio technology on soundgrains.com